<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
<script>
    /*三目运算符*/
    var age = 17;
    var msg = age > 18? "成年人" :"未成年人";
    document.write(msg);

    var numm = 23 - true;
    document.write(numm);

</script>
</html>